I've used a lot of OSes and have always found the chkconfig command on Redhat / Centos very useful for changing runlevels of services. The equivalent on Ubuntu is the fabulously unmemorably named sysv-rc-conf. (UPDATE – Ignore most of this post and read Ernest's comment below) … Here's how to get it on your system.

sudo apt-get install sysv-rc-conf

and to run it requires

sudo ..uh what was its name again sysrc something? Dammit.

So what I normally do is a quick symlink:

sudo ln -s /usr/sbin/sysv-rc-conf /usr/sbin/chkconfig

and then I can use chkconfig as if it was really available for Ubuntu. Don't know why they couldn't just stick to the same name. Bah.